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Derivative Financial Instruments (Details) bbl in Thousands, BTU in Billions | May 03, 2018 BTU $ / EnergyContent $ / Barrels bbl | Mar. 31, 2018 BTU $ / EnergyContent $ / Barrels bbl
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NYMEX Oil Swap Contract Second Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 1,534
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 49.57
NYMEX Oil Swap Contract Third Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 1,769
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 49.77
NYMEX Oil Swap Contract Fourth Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 1,894
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 49.87
NYMEX Oil Swap Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 1,940
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 50.70
NYMEX Oil Swap Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 7,137
NYMEX Oil Collar Contract Second Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 1,459
Derivative, Floor Price | $ / Barrels |  |  | 50.00
Derivative, Ceiling Price | $ / Barrels |  |  | 59.03
NYMEX Oil Collar Contract Third Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 1,948
Derivative, Floor Price | $ / Barrels |  |  | 50.00
Derivative, Ceiling Price | $ / Barrels |  |  | 58.61
NYMEX Oil Collar Contract Fourth Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 2,222
Derivative, Floor Price | $ / Barrels |  |  | 50.00
Derivative, Ceiling Price | $ / Barrels |  |  | 58.44
NYMEX Oil Collar Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 5,908
Derivative, Floor Price | $ / Barrels |  |  | 47.65
Derivative, Ceiling Price | $ / Barrels |  |  | 59.19
NYMEX Oil Collar Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 11,537
Oil Basis Swap Contract Second Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 2,392
Weighted-Average Contract Price | $ / Barrels | [1] |  | (1.03)
Oil Basis Swap Contract Third Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 3,018
Weighted-Average Contract Price | $ / Barrels | [1] |  | (1.06)
Oil Basis Swap Contract Fourth Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 3,327
Weighted-Average Contract Price | $ / Barrels | [1] |  | (1.08)
Oil Basis Swap Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 5,788
Weighted-Average Contract Price | $ / Barrels | [1] |  | (1.09)
Oil Basis Swap [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 14,525
Gas Swaps Contract Second Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent |  |  | 3.31
Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes | BTU |  |  | 23,507
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | BTU |  |  | (7,795)
Derivative, Swap Type, Weighted-Average Fixed Price, Purchased Volumes | $ / EnergyContent |  |  | 4.24
Derivative, Nonmonetary Notional Amount, Energy Measure, Net Volumes | BTU |  |  | 15,712
Gas Swaps Contract Third Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent |  |  | 3.29
Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes | BTU |  |  | 24,627
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | BTU |  |  | (7,480)
Derivative, Swap Type, Weighted-Average Fixed Price, Purchased Volumes | $ / EnergyContent |  |  | 4.23
Derivative, Nonmonetary Notional Amount, Energy Measure, Net Volumes | BTU |  |  | 17,147
Gas Swaps Contract Fourth Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent |  |  | 3.29
Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes | BTU |  |  | 25,856
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | BTU |  |  | (7,210)
Derivative, Swap Type, Weighted-Average Fixed Price, Purchased Volumes | $ / EnergyContent |  |  | 4.27
Derivative, Nonmonetary Notional Amount, Energy Measure, Net Volumes | BTU |  |  | 18,646
Gas Swaps Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent |  |  | 3.76
Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes | BTU |  |  | 41,394
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | BTU |  |  | (24,415)
Derivative, Swap Type, Weighted-Average Fixed Price, Purchased Volumes | $ / EnergyContent |  |  | 4.34
Derivative, Nonmonetary Notional Amount, Energy Measure, Net Volumes | BTU |  |  | 16,979
Gas Swaps Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes | BTU | [2] |  | 115,384
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | BTU | [2] |  | (46,900)
Derivative, Nonmonetary Notional Amount, Energy Measure, Net Volumes | BTU | [2] |  | 68,484
IF HSC [Member] |  |  |
Derivative Financial Instruments |  |  |
Index percent of natural gas fixed swaps |  |  | 100.00%
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract Second Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 915
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 10.87
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract Third Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 1,033
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 10.99
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract Fourth Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 1,146
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 11.18
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 3,533
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 12.31
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract 2020 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 539
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 11.13
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 7,166
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Second Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 554
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 24.94
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Third Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 610
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 24.27
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 671
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 24.39
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 1,503
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 27.83
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2020 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 0
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 0
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 3,338
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Second Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 84
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 35.69
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Third Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 93
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 35.70
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 102
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 35.70
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 154
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 35.64
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2020 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 0
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 0
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 433
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Second Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 66
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 35.07
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Third Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 70
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 35.07
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 76
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 35.07
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 117
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 35.70
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2020 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 0
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 0
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 329
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract Second Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 175
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 50.99
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract Third Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 202
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 51.13
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 208
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 50.99
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 197
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 50.93
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2020 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 0
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  |  | 0
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  |  | 782
Subsequent Event [Member] | NYMEX Oil Collar Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  | 2,100 |
Subsequent Event [Member] | Oil Basis Swap Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  | 500 |
Weighted-Average Contract Price | $ / Barrels |  | (3.80) |
Subsequent Event [Member] | Oil Basis Swap Contract 2020 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | bbl |  | 2,300 |
Subsequent Event [Member] | IF HSC Gas Collar Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Floor Price | $ / EnergyContent |  | 2.50 |
Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes | BTU |  | 14,242 |
Minimum [Member] | Subsequent Event [Member] | NYMEX Oil Collar Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Floor Price | $ / Barrels |  | 50.00 |
Derivative, Ceiling Price | $ / Barrels |  | 66.60 |
Minimum [Member] | Subsequent Event [Member] | Oil Basis Swap Contract 2020 [Member] |  |  |
Derivative Financial Instruments |  |  |
Weighted-Average Contract Price | $ / Barrels |  | (0.80) |
Minimum [Member] | Subsequent Event [Member] | IF HSC Gas Collar Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Ceiling Price | $ / EnergyContent |  | 2.83 |
Maximum [Member] | Subsequent Event [Member] | NYMEX Oil Collar Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Floor Price | $ / Barrels |  | 55.00 |
Derivative, Ceiling Price | $ / Barrels |  | 68.62 |
Maximum [Member] | Subsequent Event [Member] | Oil Basis Swap Contract 2020 [Member] |  |  |
Derivative Financial Instruments |  |  |
Weighted-Average Contract Price | $ / Barrels |  | (0.97) |
Maximum [Member] | Subsequent Event [Member] | IF HSC Gas Collar Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Ceiling Price | $ / EnergyContent |  | 2.84 |
[1] | Represents the price differential between WTI prices at Midland, Texas and WTI prices at Cushing, Oklahoma.
[2] | Total net volumes of gas swaps are comprised 100% of IF HSC.

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- Definition Derivative, Nonmonetary Notional Amount, Energy Measure, Net of Purchased Volumes + References No definition available. + Details
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- Definition Derivative, Oil Basis Swap Type, Weighted-Average Contract Price + References No definition available. + Details
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- Definition Derivative, Swap Type, Average Fixed Price, Purchased Volumes + References No definition available. + Details
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- Definition Average fixed price related to the group of price risk swap derivatives. + References No definition available. + Details
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